I like how her face is dark and creates a shadow. This is due to the light being position higher than she is and casting a side light toward her (45 degree angle), but instead of it shining on her face it brings attention to the hair. In this photo the main light is on her, the back light is making the background a little brighter than what it is, also creating a contrast between the darkness on her verses the color of the background. I believe there is a fill but its barley noticeable.
